DASH live stream with subtitle track doesn't show subtitles

[f1multiviewer]

Have you read the FAQ and checked for duplicate open issues?
Yes

If the problem is related to FairPlay, have you read the tutorial?

Not related to FairPlay

What version of Shaka Player are you using?

4.9.9

Can you reproduce the issue with our latest release version?
Yes

Can you reproduce the issue with the latest code from main?
Not sure how to test this

Are you using the demo app or your own custom app?
Custom app

If custom app, can you reproduce the issue using our demo app?
No because of CORS

What browser and OS are you using?
Electron, macOS

For embedded devices (smart TVs, etc.), what model and firmware version are you using?
N/A

What are the manifest and license server URIs?

Dynamic manifest, with geo-restrictions, and widevine with auth (from F1 TV), only available during live sessions, otherwise service uses DASH.

repro-case.zip (wasn't able to grab the original manifest, but got the parsed manifest for this one, then fetched a new manifest for the same media, so hopefully this is correct)

What configuration are you using? What is the output of player.getConfiguration()?

Show JSON

{
    "drm": {
        "retryParameters": {
            "maxAttempts": 2,
            "baseDelay": 1000,
            "backoffFactor": 2,
            "fuzzFactor": 0.5,
            "timeout": 30000,
            "stallTimeout": 5000,
            "connectionTimeout": 10000
        },
        "servers": {},
        "clearKeys": {},
        "advanced": {},
        "delayLicenseRequestUntilPlayed": false,
        "persistentSessionOnlinePlayback": false,
        "persistentSessionsMetadata": [],
        "logLicenseExchange": false,
        "updateExpirationTime": 1,
        "preferredKeySystems": [],
        "keySystemsMapping": {},
        "parseInbandPsshEnabled": false,
        "minHdcpVersion": "",
        "ignoreDuplicateInitData": true
    },
    "manifest": {
        "retryParameters": {
            "maxAttempts": 2,
            "baseDelay": 100,
            "backoffFactor": 2,
            "fuzzFactor": 0.5,
            "timeout": 30000,
            "stallTimeout": 5000,
            "connectionTimeout": 10000
        },
        "availabilityWindowOverride": null,
        "disableAudio": false,
        "disableVideo": false,
        "disableText": false,
        "disableThumbnails": false,
        "defaultPresentationDelay": 0,
        "segmentRelativeVttTiming": false,
        "raiseFatalErrorOnManifestUpdateRequestFailure": false,
        "dash": {
            "clockSyncUri": "https://api.multiviewer.app/api/v1/time",
            "ignoreDrmInfo": false,
            "disableXlinkProcessing": false,
            "xlinkFailGracefully": false,
            "ignoreMinBufferTime": true,
            "autoCorrectDrift": false,
            "initialSegmentLimit": 1000,
            "ignoreSuggestedPresentationDelay": true,
            "ignoreEmptyAdaptationSet": false,
            "ignoreMaxSegmentDuration": false,
            "keySystemsByURI": {
                "urn:uuid:1077efec-c0b2-4d02-ace3-3c1e52e2fb4b": "org.w3.clearkey",
                "urn:uuid:e2719d58-a985-b3c9-781a-b030af78d30e": "org.w3.clearkey",
                "urn:uuid:edef8ba9-79d6-4ace-a3c8-27dcd51d21ed": "com.widevine.alpha",
                "urn:uuid:9a04f079-9840-4286-ab92-e65be0885f95": "com.microsoft.playready",
                "urn:uuid:79f0049a-4098-8642-ab92-e65be0885f95": "com.microsoft.playready"
            },
            "sequenceMode": false,
            "enableAudioGroups": false,
            "multiTypeVariantsAllowed": true,
            "useStreamOnceInPeriodFlattening": false,
            "updatePeriod": -1,
            "enableFastSwitching": true
        },
        "hls": {
            "ignoreTextStreamFailures": false,
            "ignoreImageStreamFailures": false,
            "defaultAudioCodec": "mp4a.40.2",
            "defaultVideoCodec": "avc1.42E01E",
            "ignoreManifestProgramDateTime": false,
            "ignoreManifestProgramDateTimeForTypes": [],
            "mediaPlaylistFullMimeType": "video/mp2t; codecs=\"avc1.42E01E, mp4a.40.2\"",
            "useSafariBehaviorForLive": true,
            "liveSegmentsDelay": 1,
            "sequenceMode": true,
            "ignoreManifestTimestampsInSegmentsMode": false,
            "disableCodecGuessing": false,
            "disableClosedCaptionsDetection": false,
            "allowLowLatencyByteRangeOptimization": true
        },
        "mss": {
            "sequenceMode": false,
            "keySystemsBySystemId": {
                "9a04f079-9840-4286-ab92-e65be0885f95": "com.microsoft.playready",
                "79f0049a-4098-8642-ab92-e65be0885f95": "com.microsoft.playready"
            }
        }
    },
    "streaming": {
        "retryParameters": {
            "maxAttempts": 10,
            "baseDelay": 200,
            "backoffFactor": 2,
            "fuzzFactor": 0.5,
            "timeout": 10000,
            "stallTimeout": 5000,
            "connectionTimeout": 10000
        },
        "rebufferingGoal": 0.1,
        "bufferingGoal": 60,
        "bufferBehind": 60,
        "evictionGoal": 1,
        "ignoreTextStreamFailures": true,
        "alwaysStreamText": false,
        "startAtSegmentBoundary": true,
        "gapDetectionThreshold": 0.1,
        "gapJumpTimerTime": 0.25,
        "durationBackoff": 0,
        "safeSeekOffset": 5,
        "stallEnabled": true,
        "stallThreshold": 1,
        "stallSkip": 0.1,
        "useNativeHlsOnSafari": true,
        "useNativeHlsForFairPlay": true,
        "inaccurateManifestTolerance": 0,
        "lowLatencyMode": true,
        "autoLowLatencyMode": false,
        "forceHTTP": false,
        "forceHTTPS": false,
        "preferNativeHls": false,
        "updateIntervalSeconds": 0.1,
        "dispatchAllEmsgBoxes": false,
        "observeQualityChanges": false,
        "maxDisabledTime": 1,
        "parsePrftBox": false,
        "segmentPrefetchLimit": 5,
        "prefetchAudioLanguages": [],
        "disableAudioPrefetch": false,
        "disableTextPrefetch": false,
        "disableVideoPrefetch": false,
        "liveSync": false,
        "liveSyncTargetLatencyTolerance": 0.5,
        "liveSyncMaxLatency": 1,
        "liveSyncPlaybackRate": 1.1,
        "liveSyncMinLatency": 0,
        "liveSyncMinPlaybackRate": 0.95,
        "liveSyncPanicMode": false,
        "liveSyncPanicThreshold": 60,
        "allowMediaSourceRecoveries": true,
        "minTimeBetweenRecoveries": 5,
        "vodDynamicPlaybackRate": false,
        "vodDynamicPlaybackRateLowBufferRate": 0.95,
        "vodDynamicPlaybackRateBufferRatio": 0.5,
        "infiniteLiveStreamDuration": false,
        "preloadNextUrlWindow": 30,
        "loadTimeout": 30,
        "clearDecodingCache": false
    },
    "mediaSource": {
        "codecSwitchingStrategy": "smooth",
        "forceTransmux": false,
        "insertFakeEncryptionInInit": true
    },
    "offline": {
        "usePersistentLicense": true,
        "numberOfParallelDownloads": 5
    },
    "abr": {
        "enabled": true,
        "useNetworkInformation": true,
        "defaultBandwidthEstimate": 10000000,
        "switchInterval": 8,
        "bandwidthUpgradeTarget": 0.85,
        "bandwidthDowngradeTarget": 0.95,
        "restrictions": {
            "minWidth": 0,
            "maxWidth": null,
            "minHeight": 0,
            "maxHeight": null,
            "minPixels": 0,
            "maxPixels": null,
            "minFrameRate": 0,
            "maxFrameRate": null,
            "minBandwidth": 0,
            "maxBandwidth": null,
            "minChannelsCount": 0,
            "maxChannelsCount": null
        },
        "advanced": {
            "minTotalBytes": 128000,
            "minBytes": 16000,
            "fastHalfLife": 2,
            "slowHalfLife": 5
        },
        "restrictToElementSize": false,
        "restrictToScreenSize": false,
        "ignoreDevicePixelRatio": false,
        "clearBufferSwitch": false,
        "safeMarginSwitch": 0,
        "cacheLoadThreshold": 20
    },
    "autoShowText": 3,
    "preferredAudioLanguage": "",
    "preferredAudioLabel": "",
    "preferredTextLanguage": "",
    "preferredVariantRole": "",
    "preferredTextRole": "",
    "preferredAudioChannelCount": 2,
    "preferredVideoHdrLevel": "AUTO",
    "preferredVideoLayout": "",
    "preferredVideoLabel": "",
    "preferredVideoCodecs": [],
    "preferredAudioCodecs": [],
    "preferForcedSubs": false,
    "preferSpatialAudio": false,
    "preferredDecodingAttributes": [],
    "restrictions": {
        "minWidth": 0,
        "maxWidth": null,
        "minHeight": 0,
        "maxHeight": null,
        "minPixels": 0,
        "maxPixels": null,
        "minFrameRate": 0,
        "maxFrameRate": null,
        "minBandwidth": 0,
        "maxBandwidth": null,
        "minChannelsCount": 0,
        "maxChannelsCount": null
    },
    "playRangeStart": 0,
    "playRangeEnd": null,
    "textDisplayer": {
        "captionsUpdatePeriod": 0.25
    },
    "cmcd": {
        "enabled": false,
        "sessionId": "",
        "contentId": "",
        "rtpSafetyFactor": 5,
        "useHeaders": false,
        "includeKeys": []
    },
    "cmsd": {
        "enabled": true,
        "applyMaximumSuggestedBitrate": true,
        "estimatedThroughputWeightRatio": 0.5
    },
    "lcevc": {
        "enabled": false,
        "dynamicPerformanceScaling": true,
        "logLevel": 0,
        "drawLogo": false
    },
    "ads": {
        "customPlayheadTracker": false,
        "skipPlayDetection": false,
        "supportsMultipleMediaElements": true
    }
}

What did you do?

1. Play manifest
2. Enable subtitles

What did you expect to happen?
Subtitles show up (they do in other players, namely Bitmovin)

What actually happened?

No subtitles show up. They are being fetched, parsed, and added but it almost seems like either the timestamp is parsed wrong, or they are not showing outside of the bounds of the segment?

If I disable this code:

shaka-player/lib/text/ttml_text_parser.js

Lines 334 to 338 in 88d2a02

	// Clip times to segment boundaries.
	// https://github.com/shaka-project/shaka-player/issues/4631
	start = Math.max(start, timeContext.segmentStart);
	end = Math.min(end, timeContext.segmentEnd);

They do show up, just duplicated.

Are you planning send a PR to fix it?
I'm not sure I have the experience with Shaka that requires this.

[f1multiviewer]

We have supplied additional test instructions and a manifest to [email protected]

[the-alexandra-k]

@joeyparrish moving from email. The details were sent to [email protected]

[the-alexandra-k]

@theodab Did you have a chance to take a look at the details we emailed?

[f1multiviewer]

If more information is required, please let us know. We'd be more than happy to provide additional data wherever we can. Thank you.

[the-alexandra-k]

@avelad @theodab hey guys, any insight here?

[the-alexandra-k]

@joeyparrish bringing this back up :)

[joeyparrish]

Sorry, we haven't had time to work on this.

No subtitles show up. They are being fetched, parsed, and added but it almost seems like either the timestamp is parsed wrong, or they are not showing outside of the bounds of the segment?

I recommend you check the following:

1. If you're using the UI, get the Player with player = video.ui.getControls().getLocalPlayer() and then check (uncompiled): player.mediaSourceEngine_.textDisplayer_.cues_ (in compiled or debug builds, you will need to find the minified names). That will let you see easily what cues have been parsed and sent for display.
2. If you're not using the UI, try video.textTracks[0].cues for the same.

This will help you determine if the timestamps are the root of the problem. We can try to guide you further from there.

[shaka-bot]

Closing due to inactivity. If this is still an issue for you or if you have further questions, the OP can ask shaka-bot to reopen it by including @shaka-bot reopen in a comment.